Solution structure of the human Grb14-SH2 domain and comparison with the structures of the human Grb7-SH2/erbB2 peptide complex and human Grb10-SH2 domain.

1Department of Biochemistry, College of Medicine, University of Vermont, Burlington, Vermont 05405, USA.

Abstract

Grb14 is an adapter protein that is known to be overexpressed in estrogen receptor positive breast cancers, and in a number of prostate cancer cell lines. Grb14 has been demonstrated to bind to a number of activated receptor tyrosine kinases (RTKs) and to modulate signals transduced through these receptors. The RTKs to which Grb14 binds include the insulin receptor (IR), the fibroblast growth factor receptor (FGFR), the platelet-derived growth factor receptor (PDGFR), and the tunica endothelial kinase (Tek/Tie2) receptor. Grb14 has been shown to bind to these activated RTKs through its Src homology 2 (SH2) domain, with the exception of the insulin receptor, where the primary binding interaction is via a small domain adjacent to the SH2 domain (the BPS or PIR domain). Grb14 is a member of the Grb7 family of proteins, which also includes Grb7 and Grb10. We have solved the solution structure of the human Grb14-SH2 domain and compared it with the recently determined Grb7-SH2 and Grb10-SH2 domain structures.

Backbone-trace stereo views of 20 representative NMR solution structures of the human Grb14–SH2 domain. Residues 16–114 are visualized. The orientation of the Grb14–SH2 domain in the figure is the same as that shown in Figure 2. The structures were selected based upon the lowest NOE violation energies out of 50 calculated structures.

(A) Ribbon representation of one of the 20 representative NMR solution structures of the human Grb14–SH2 domain (gold) aligned with a representative structure of the Grb7–SH2/erbB2 peptide complex (mauve). Secondary structural elements are labeled from the N terminus to the C terminus, with αA being the N-terminal α-helix, αB the C-terminal α-helix, etc. The approximate location of the insertion described in the text is indicated by a transparent blue box. (B) Ribbon representation of one of the 20 representative NMR solution structures of the human Grb14–SH2 domain (gold) aligned with the X-ray crystallographic structure of the Grb10–SH2 domain (mauve; ). The N and C termini are labeled.